Conventionally, in the case of using a telephone set, for instance, in a dry area of low relative humidity, there is a possibility that electrostatic charge retained on an user can be discharged to a metal portion of the receiver and/or transmitter of a telephone handset, which can cause failure of an electronic circuit incorporated in the telephone set, resulting in the failure of communication. In addition, the discharge is startling, very annoying and is sometimes painful to the user.